Experimental and Theoretical Electronic Structure and Symmetry Effects in Ultrathin NbSe2 Films

Abstract

Layered quasi-two-dimensional transition metal dichalcogenides (TMDCs), which can be readily made in ultrathin films, offer excellent opportunities for studying how dimensionality affects electronic structure and physical properties. Among all TMDCs, NbSe2 is of special interest; bulk NbSe2 hosts a charge-density-wave phase at low temperatures and has the highest known superconducting transition temperature, and these properties can be substantially modified in the ultrathin film limit. Motivated by these effects, we report herein a study of few-layer NbSe2 films, with a well-defined single-domain orientation, epitaxially grown on Gallium Arsenide (GaAs). Angle-resolved photoemission spectroscopy (ARPES) was used to determine the electronic band structure and the Fermi surface as a function of layer thickness; first-principles band structure calculations were performed for comparison. The results show interesting changes as the film thickness increases from a monolayer (ML) to several layers. The most notable changes occur between a ML and a bilayer, where the inversion symmetry in bulk NbSe2 is preserved in the bilayer but not in the ML. The results illustrate some basic dimensional effects and provide a basis for further exploring and understanding the properties of NbSe2.

15 pages, 4 figures

References in corpus (16)

• The electronic properties of graphene
• Atomically thin MoS2: A new direct-gap semiconductor
• Two Dimensional Atomic Crystals
• Evidence of Ising pairing in superconducting NbSe${}_2$ atomic layers
• Strongly enhanced charge-density-wave order in monolayer NbSe${}_2$
• Characterization of collective ground states in single-layer NbSe2
• Fermi surface nesting and the origin of Charge Density Waves in metals
• Extended Phonon Collapse and the Origin of the Charge-Density-Wave in NbSe${}_2$
• Fermi Surface Nesting and the Origin of the Charge Density Wave in NbSe${}_2$
• A precise method for visualizing dispersive features in image plots
• Effect of dimensionality on the charge-density-wave in few-layers 2H-NbSe${}_2$
• Two energy gaps and Fermi surface 'arcs' in NbSe2
• Ising Superconductivity and Quantum Phase Transition in Macro-Size Monolayer NbSe2
• Quasi-Particle Spectra, Charge-Density-Wave, Superconductivity and Electron-Phonon Coupling in 2H-NbSe2
• Ising Superconductivity and Majorana Fermions in Transition Metal Dichalcogenides
• Charge Order from Orbital-dependent Coupling Evidenced by NbSe${}_2$

Cited by in corpus (6)

• Electronic structure of quantum materials studied by angle-resolved photoemission spectroscopy
• Crossover of Ising- to Rashba-Type Superconductivity in Epitaxial Bi2Se3/Monolayer NbSe2 Heterostructures
• Morphology Control of Epitaxial Monolayer Transition Metal Dichalcogenides
• A novel $\sqrt{19}\times \sqrt{19}$ superstructure in epitaxially grown 1T-TaTe${}_2$
• One-dimensional electronic states in a natural misfit structure
• Unveiling resilient superconducting fluctuations in atomically thin NbSe${}_2$ through Higgs mode spectroscopy